This invention is in the area of the topical treatment of cutaneous, ocular, and mucosal hypersensitivity and hyperproliferative conditions induced by or associated with an immune response, that includes the application of an effective amount of buspirone or a buspirone derivative, or a pharmaceutically acceptable salt thereof, optionally in a pharmaceutically acceptable carrier.
The immune system specifically recognizes and selectively eliminates foreign invaders, or other antigenic agents, by a process known as the immune response. The immune response has three major characteristics: it responds adaptively to foreign invaders, it exhibits strong specificity, and it displays a long-term memory of earlier contacts with specific foreign pathogens or antigens. The immune response involves the production of antibodies and/or the destruction of antigenic cells by T lymphocytes; both the antibodies and the T lymphocytes are highly specific for the antigen or hapten.
The immune response can provide great benefit to the host when directed against an infectious organism. As an example, an important component of current public health practices is the use of vaccines to elicit immune responses against infectious organisms that cause severe illness and death. However, when directed against agents that are relatively innocuous, such as pollen, animal dander, and certain plant resins, the cells, antibodies, and mediators which represent the effector components of the immune response can cause damage to the host's tissues that is out of proportion to any threat to health posed by the antigenic agent that first elicited the response.
For example, cutaneous contact hypersensitivity responses are complex expressions of cellular immunity characterized by antigen-dependent changes in lymphocyte traffic, the recruitment of circulating leukocytes to the site of antigen challenge (leukocyte infiltration) and alterations in vascular permeability and blood flow resulting in tissue swelling (edema). In humans and companion animals, cutaneous contact hypersensitivity responses can occur on exposure to certain plant resins, such as those of poison ivy, and other commonly encountered agents in the environment. In individuals sensitized to such commonly encountered agents, a severe contact reaction can result upon exposure, with significant associated morbidity. Severe or repeated contact hypersensitivity reactions can be followed by significant chronic changes, such as scarring of affected tissues, itchiness, swelling, scaling and oozing of tissue fluid through the skin surface. This pathology may predispose the patient to bacterial superinfection. In the eye, chronic immune responses can lead to diminished vision or actual blindness. In the lung, chronic immune responses, such as chronic allergic asthma, can result in serious chronic lung disease.
Cutaneous contact hypersensitivity and asthma are just two examples of immune responses that can be associated with significant morbidity. Others include atopic dermatitis, eczema, psoriasis, Sjogren's Syndrome, including keratoconjunctivitis sicca secondary to Sjogren's Syndrome, alopecia areata, allergic responses due to arthropod bite reactions, Crohn's disease, aphthous ulcer, iritis, conjunctivitis, keratoconjunctivitis, ulcerative colitis, lichen planus, asthma, allergic asthma, cutaneous lupus erythematosus, scleroderma, vaginitis, proctitis, and drug eruptions. These conditions may result in any one or more of the following symptoms or signs: itching, swelling, redness, blisters, crusting, ulceration, pain, scaling, cracking, hair loss, scarring, or oozing of fluid involving the skin, eye, or mucosal membranes.
In atopic dermatitis, and eczema in general, immunologically mediated leukocyte infiltration (particularly infiltration of mononuclear cells, lymphocytes, neutrophils, and eosinophils) into the skin importantly contributes to the pathogenesis of these diseases. Chronic eczema also is associated with significant hyperproliferation of the epidermis. Similarly, psoriasis, a common cutaneous disease associated with a hyperproliferating epidermis, also has a leukocyte infiltration component. Immunologically mediated leukocyte infiltration also occurs at sites other than the skin, such as in the airways in asthma and in the tear producing gland of the eye in keratoconjunctivitis sicca.
It is now believed that leukocytes and other cells found in the normal and abnormal skin, eye, or mucosal membranes secrete a variety of cytokines. During immunological responses affecting these sites, cytokines are important in recruiting additional leukocytes into these tissues, in promoting epithelial hyperproliferation, and in inducing other chronic changes such as scarring. For example, eosinophils, a type of granulocyte found in many pathological immune responses including atopic dermatitis and asthma, can produce the cytokine TGF-.alpha. (Wong D. T. W., Weller P. F., Galli, S. J., Elovic A., Rand, T. H., Gallagher, G. T., Chiang, T., Chou, M. Y., Matossian, K., McBride, J., Todd, R. Human eosinophils express transforming growth factor-alpha. J. Exp. Med. 1990; 172:673-81), which promotes epithelial hyperproliferation, and TGF-.beta. (Wong, D. T. W., Elovic, A., Matossian, K., Nagura, N., McBride, J., Chou, M. Y., Gordon, J. R., Rand, T. H., Galli, S. J., Weller, P. F. Eosinophils from patients with blood eosinophilia express transforming growth factor .beta.1. Blood 1991; 78:2702-2707), which promotes fibrosis.
In addition to disorders that clearly represent pathological consequences of immune responses, immune responses are thought to contribute to many other pathological conditions, including Crohn's disease and ulcerative colitis of the gastrointestinal tract, psoriasis, alopecia areata and others. While the cause of most of these disorders is unclear, it is thought that exogenous agents yet to be defined or components of the host's own tissues (in the case of autoimmune disorders) may provoke an immune response that is responsible for the infiltration of lymphocytes, monocytes, and granulocytes observed in these conditions. It is also believed that the infiltrating cells significantly contribute to the tissue pathology associated with these disorders, through the production of cytokines as well as by other mechanisms.
The need to control the wide variety of pathological responses with immunological components which result in cutaneous, ocular, or mucosal hypersensitivity reactions, hyperproliferation, and scarring has led to a search for therapeutic agents that are both safe and effective.
Because of the importance of leukocytes and their products in the development of pathology associated with immune responses, many approaches to treating these conditions are focused on inhibiting the immune responses and leukocyte infiltration contributing to these disorders. Several substances are known to be able to inhibit the immune responses contributing to cutaneous leukocyte responses or hyperproliferative responses. Corticosteroids, when administered systemically, are effective in this regard but are associated with significant and potentially dangerous side effects. Topically applied corticosteroids have some efficacy in treating these conditions, but are only partially effective in many instances and have their own significant side effects, including atrophy of tissue, formation of telangiectasia, blanching, and a myriad of systemic effects if significantly absorbed. Other agents with partial utility for treating some of the above conditions include psoralen plus ultraviolet A (PUVA), cyclosporin A, or azathioprine, but the risk-to-benefit ratios for these agents is unfavorable for most of the conditions described above.
As a result, there is a significant and very long-standing need to identify new agents with favorable benefit to risk ratios that can be applied topically to prevent or suppress (i.e. "treat") immune responses contributing to cutaneous, ocular, or mucosal hypersensitivity reactions, hyperproliferation and scarring. Optimally, such agents should be effective when applied locally, and systemic absorption should not result in blood levels high enough to cause significant systemic toxicity or other adverse side effects. Not only does local administration place the agent in closest contact with the site needing treatment, but it also diminishes the possibility that such treatment will suppress beneficial immune responses which may occur at other, more distant, sites.
In contrast to the immune response, an inflammatory response is a pathologic condition that can occur in response to immunologically non-specific injury, either from physical (such as trauma), chemical, or biologic agents. An inflammatory response is characterized by increased blood flow and redness in the inflamed area, increased capillary permeability and edema, and recruitment of immunologically non-specific white blood cells, especially neutrophils, that remove injurious material and promote repair. Unlike immune responses, inflammatory responses do not respond adaptively to the inciting stimulus, do not show specificity and do not exhibit long term memory. Cellular products of lymphocytes may contribute to or induce an inflammatory response. However, because of the differences in mechanisms, a compound can function as an anti-inflammatory agent without having immunosuppressive properties. Phenylbutazone, indomethacin, aspirin, ibuprofen, and acetaminophen are examples of anti-inflammatory compounds which have no significant immunosuppressive activity, as demonstrated by their lack of a significant effect on immunologically mediated responses, such as contact hypersensitivity.
PCT International Publication No. WO 91/02527 discloses a method and composition to treat cutaneous, mucosal, or ocular hypersensitivity that includes administering an effective amount of reserpine, spiperone, or other serotonin antagonist.
Buspirone (8-[4-[4-(2-pyrimidinyl)-1-piperaziny]butyl]-8-azaspiro[4.5][decane-7,9-di one) is a neuroleptic agent with known central nervous system (CNS) dopamine and serotonin (5-HT) receptor antagonist properties.
It is an object of the present invention to present a method for the topical treatment of cutaneous, mucosal and ocular pathology associated with immune responses.
It is yet another object of the present invention to present a method for the topical treatment of cutaneous, mucosal, or ocular hypersensitivity and epithelial hyperproliferation.
It is yet another object of the invention to present a method for the topical treatment of cutaneous, mucosal or ocular scarring.